TY - JOUR T1 - Prognosis of Seronegative Patients in a Large Prospective Cohort of Patients with Early Inflammatory Arthritis JF - The Journal of Rheumatology JO - J Rheumatol DO - 10.3899/jrheum.140082 SP - jrheum.140082 AU - Lillian Barra AU - Janet E. Pope AU - John E. Orav AU - Gilles Boire AU - Boulos Haraoui AU - Carol Hitchon AU - Edward C. Keystone AU - J. Carter Thorne AU - Diane Tin AU - Vivian P. Bykerk AU - the CATCH Investigators Y1 - 2014/10/01 UR - http://www.jrheum.org/content/early/2014/09/25/jrheum.140082.abstract N2 - Objective Rheumatoid factor (RF) and anticitrullinated protein antibodies (ACPA) are believed to be associated with more severe rheumatoid arthritis; however, studies in early inflammatory arthritis (EIA) have yielded conflicting results. Our study determined the prognosis of baseline ACPA-negative and RF-negative patients. Methods Patients enrolled in the Canadian Early Arthritis Cohort had IgM RF and IgG anticyclic citrullinated peptide antibodies 2 (anti-CCP2) measured at baseline. Remission was defined as a Disease Activity Score of 28 joints (DAS28) < 2.6 using logistic regression accounting for confounders at 12-month and 24-month followup. Results Of the 841 patients, 216 (26%) were negative for both RF and anti-CCP2. Compared to seropositive subjects, seronegative subjects were older (57 ± 15 vs 51 ± 14 yrs), more males proportionately (31% vs 23%), and had shorter length of symptoms (166 ± 87 vs 192 ± 98 days), and at baseline had higher mean swollen joint count (SJC; 8.8 ± 6.8 vs 6.5 ± 5.6), DAS28 (5.0 ± 1.6 vs 4.8 ± 1.5), and erosive disease (32% vs 24%, p < 0.05). Treatment was similar between the 2 groups. At 24-month followup, seronegative compared to seropositive subjects had greater mean change (Δ ± SD) in disease activity measures: ΔSJC counts (–6.9 ± 7.0 vs –5.1 ± 5.9), ΔDAS28 (–2.4 ± 2.0 vs –1.8 ± 1.8), and ΔC-reactive protein (–11.0 ± 17.9 vs –6.4 ± 17.5, p < 0.05). Accounting for confounders, antibody status was not significantly associated with remission. However, at 12-month followup, ACPA-positive subjects were independently more likely to have new erosive disease (OR 2.94, 95% CI 1.45–5.94). Conclusion Although seronegative subjects with EIA have higher baseline DAS28 compared to seropositive subjects, they have a good response to treatment and are less likely to develop erosive disease during followup. ER -